Abstract

Recent improvements of observational and numerical techniques have permitted to unveil the wide diversity of star forming clouds, in the Milky Way but also in other nearby galaxies. The variety in the morphology and dynamics of these clouds, as a function of their galactic environment, strongly suggests a complex interplay between global (kpc-scale) and local (pc-scale) processes, that remains to be fully understood. The coupling between large-scale structures, turbulence, self-gravity, magnetic fields and feedback makes this problem one of the most challenging of modern astrophysics, and implies major implications for both the smaller and larger scales. Using a set of (sub)parsec-resolution hydrodynamical simulations of galaxies including local spirals, mergers and high redshift disks, I will illustrate the diversity of star formation in simulations and compare to what is observed. I will emphasise the role of the variation of physical conditions within a single disk galaxy and then explore the differences from galaxy to galaxy. After a brief review on our understanding of star formation, I will propose a new theory on its triggering in galaxy mergers.